you can dublicate all basic objects and group them together in a sub folder. This sub folder you can save as a library. All objects within the library can be modified in any way.
Everytime you start a new project, you can load your specific library as a template for your simulation model.
You also can create new versions of your library and update your simulation models with the new versions. To do so, enter the directory path of your library in File->Preferences->Libraries directories. This enables Plant simulation to check for new libraries of your own.